sql Method for adding fields and notes to a table

1. Add fields:

alter table table name ADD field name type;

eg:

alter table sys_cwzd ADD SCCLLJ VARCHAR2(50); 

2. Add remarks:

comment on column  Table name . Field name  is ' Note name ';

eg:

comment on column sys_cwzd.SCCLLJ is ' Upload material path ';

Content extension:

Add a new field:

alter table bulletin add citycode varchar(6) not null default 0; #  City code 

1. Set encoding when you create a database

create database test character set utf8;

2. Set encoding when creating tables

create table test(id int primary key)DEFAULT charset=utf8;

3. Modify the database coding

alter database test character set utf8;

4. Modify the table default encoding

alter table test character set utf8;